- Posts: 55
- Comments: 507
- Overall: 562
The 8″ twist for ARs in 5.56/223 flavor was/is intended for match bullets of 68 to 85 gr in the 2500 – 2800 fps range. Most lighter weight bullets are thinner jacketed and intended for explosiveness on small varmints. At velocities above 2700 – 2800 fps they bulge or fly apart because of the extreme RPM which is the cause of poor accuracy. Those bullets that do hold together do so because they have thick jackets. That means the terminal explosiveness you may desire or want won’t be there, especially at longer ranges.
I suggest trying the Sierra 55 gr Blitz Kings (not to be confused with the very thin jacketed 55 gr Blitz bullets). They have performed well in a couple 8 and 9″ twist ARs I’ve worked with. Start low and work up. Accuracy will go south when/if the bullet can not hold up to the RPM.